This invention relates to new X-ray contrast agents.
Iodine-containing, water-soluble X-ray contrast media are utilized for urography, angiography, myelography, gastrography, computerized tomography, and digital radiography. Additionally, there are other body cavities whose imaging is desired, such as, for example, the articular cavity, the bile duct, the bladder, and the pancreatic duct. It has been clearly apparent for some time that a single X-ray contrast medium cannot satisfy the requirements of such a large number of applications.
Use of the presently available X-ray contrast media is precluded for certain indications, or at least leaves much to be desired, for various reasons, e.g., due to inadequate compatibility in one or another respect, insufficient solubility, concentration, unsuitable pharmacokinetic properties, etc.
Substantial progress has been made with regard to the compatibility of these compounds by the development of nonionic X-ray contrast media in place of the heretofore known ionic contrast media. Special properties of these new media include low painfulness in angiography, small effects on the circulation, and small epileptogenic effect. The clinical experience gained in the meantime with nonionic and readily water-soluble X-ray contrast media (see, e.g., B. Hammer and W. Lackner: "Iopamidol, a New Non-Ionic Hydrosoluble Contrast Medium for Neuroradiology"; Neuroradiology 19:119-121, 1980) showed, on the other hand, that even the most recent opacifying compounds, among which are, for example, iopamidol, metrizamide, and iohexol, still are not devoid of side effects.